The present invention relates to a combined radar detector, speed measuring device and printer for verifying vehicle speed. In the prior art, radar detectors and speed measuring devices are known. However, Applicants are unaware of any single device which combines all of the elements of the present invention into a single workable design.
The following prior art is known to Applicants:
U.S. Pat. No. 5,049,885 to Orr PA1 U.S. Pat. No. 5,083,129 to Valentine et al. PA1 U.S. Pat. No. 5,164,729 to Decker et al.
Each of these references teaches a radar detecting device. To Applicants' knowledge, none of these references teaches the combination of elements described in this patent application.
The present invention was developed, mainly because, often, motorists receive speeding tickets which are not deserved. Three main reasons why speeding tickets are not deserved include (1) improper calibration of police radar equipment, (2) operation of police radar equipment by inexperienced police personnel, and (3) improper target identification. In this latter category, it is well known that the strength of a signal being employed by police personnel to measure vehicle speed, when that signal is sensed at the police vehicle, is inversely proportional to the fourth power of the distance (D.sup.4) between the police vehicle and the intended target. This is because the strength of the signal decreases proportional to D.sup.2 from the police vehicle to the target and again proportional to D.sup.2 from the target back to the vehicle. Furthermore, as is also known, the strength of the reflected signal is proportional to the surface area of the target. Thus, for example, the surface area of the front of the cab of an 18 wheel truck may be five times as large as the surface area of the front of an ordinary car. Thus, if such a car and truck are traveling side-by-side, the reflected signal from the truck will be five times as strong as that of the car. Thus, it should be understandable that when such a truck is following a car, it is quite possible that a speed measuring device will measure the speed of the truck even though the car is closer to the police vehicle. Thus, it often occurs that police radar measures a larger vehicle further away from the police radar than the smaller vehicle which is eventually stopped and whose owner is subsequently charged with a speeding offense. It is with these aspects in mind that the present invention was developed.